宁做“鸡头”不做“凤尾”?——新高考背景下优质高中对学生学业表现的影响

基于某新高考省份高中毕业生的大规模问卷调查数据,使用断点回归方法研究进入不同梯队优质高中对学生高考成绩、选科选考及学习投入的影响。研究发现:从学业成绩来看,优质高中并没有显著提升学生的高考成绩;相比在第二梯队优质高中做“鸡头”,勉强进入第一梯队优质高中的“凤尾”学生甚至可能面临成绩损失。从学习行为来看,“鸡头”和“凤尾”学生在选科选考和学习投入方面差异不大;相比非优质高中的“鸡头”,第二梯队优质高中的“凤尾”学生更晚确定选考科目、校内学习投入更少;相比第二梯队优质高中的“鸡头”,第一梯队优质高中的“凤尾”学生的校内学习投入更多、但学习效率更低。本文的研究发现侧面验证了政府部门监管择校、实施教育资源均衡政策的必要性。

Investigation of Al2O3 and Fe2O3 transmission and transformation during the decomposition of phosphogypsum

Phosphogypsum(PG) is a solid waste produced in the phosphate fertilizer industry and is environmentally harmful.The decomposition of PG to recycle calcium and sulfur is a proper way to reutilize PG. Current work aims at enriching the basic theory of coal decomposition process of PG. The emphasis was laid on the exploration of impact of main impurities on the process. On the other hand, according to Reaction Module, Equilib Module, and Phase Diagram Module of FactS age, the simulation computation was done on the systems of pure gypsum mixed with coal,with or without impurities for avoiding other impurities interference. Later, possible reactions in the process were deduced. Additionally, experiments were conducted in a TG-DTA integrated thermal gravimetric analyzer and a tube furnace. The products from the experiments were characterized and analyzed to verify the accuracy of theoretical calculations. The results showed that these impurities can change the decomposition process of PG. For example, aluminum oxide was transformed to calcium sulfoaluminate, while iron oxide was transformed to dicalcium ferrite. Furthermore, the results help to further improve the basic theory of phosphogypsum decomposition.

Modified corn-core powder for enhancing sludge dewaterability:Synthesis,characterization and sludge dewatering performance

The high water content of sludge has always posed significant challenges for its treatment.Synthetic flocculants,which are widely used in sewage treatment plants,can cause secondary pollution during their production and use.Thus,natural polymer flocculants made of natural materials have received increased research attention recently.Corncore,an agricultural waste,was modified through alkalization with sodium hydroxide(NaOH)and etherification with cetyltrimethylammonium bromide(CTMAB)in this study.The L16(45)orthogonal array was used to study the modification conditions.The moisture content(MC)of treated sludge was reduced by approximately 37%with the addition of modified corncore powder(MCCP),which was synthesized under optimal conditions.In addition,changes in the functional groups of the material before and after modification were determined by FTIR.Thermogravimetric analysis indicated that MCCP was steady at room temperature,moreover,BET analysis showed that MCCP had greater surface area.The microstructures of material before and after modification were examined by scanning electron microscopy,revealing that MCCP had a flakeshaped structure and had an increased area of contact area with sludge particles.MCCP is a dehydrating agent that can enhance sludge dewaterability through charge neutralization and reagglomeration and provide superior economic benefits.

Epidemiological Characteristics of Maize Rough Dwarf Disease in Huang-Huai-Hai Plain

Maize rough dwarf disease is a common epidemic disease in large areas.Its epidemic and occurrence mechanism is a complex process.In this paper,the epidemiological characteristics and influencing factors of maize rough dwarf disease in Huang-Huai-Hai plain were elaborated based on the research results of maize rough dwarf disease at home and abroad for many years.The epidemic of maize rough dwarf disease is affected by many factors,such as the occurrence and virus carrying rate of the first generation small brown planthopper,accumulation of virus sources on gramineous crops and weed hosts,maize variety resistance,maize sowing date,maize growth period,crop layout,tillage system,climate and ecological environment.The key factors causing the outbreak and epidemic of maize rough dwarf disease are the planting of maize susceptible varieties,the meeting of maize seedling stage and the peak period of adult spread of the first generation of small brown planthopper.

Effective Trace Acquirement during Product Information Diffusion and Application

Information dissemination has become part of people’s daily communication and there is great interest for both academic and industrial communities. Most previous studies have focused on the strategy and mechanisms. The methods controlling the process of information diffusion have rarely been studied. Thus, previous studies have failed to effectively mine the value of product information diffusion on social networks. In this study, based on the information diffusion product in consumer self-organized social networks, the control of the product information diffusion process was explored. The node identification principle of the QR code sender designed in this study and the linked list that associated information with specific nodes allowed the acquisition of effective traces in long-chain transmission from the information source to the value nodes, and solved user information disclosure during the transmission process. This method was applied to the tracing system of defective vehicles, achieving accurate recall of defective vehicles.

高校毕业生返乡就业的性别差异：趋势与特点

本文以推拉理论为基础,利用2003-2013年全国高校毕业生就业调查数据,分析了毕业生返乡就业中的性别差异,研究发现:女性返乡就业的热情逐渐高涨,且多在事业单位就业,而返乡就业的男性多在国有企业就业;返乡就业的女性在省会城市或直辖市就业的比例略高,而男性的就业满意度更高。在控制了个人和家庭基本特征及各省的经济发展水平、房价等变量后,女性比男性返乡就业的可能性更大,到生源省和院校省以外的他省就业的可能性更小;中部生源的女性更加倾向于返乡就业,东部生源的女性更加倾向于返乡就业而非他省就业,西部生源的女性更加倾向于院校地就业;男性返乡就业所受到的影响因素更为一致,如家庭背景、地方经济发展水平、生源省与院校省的距离等。文章据此提出了进一步的政策建议。

耐酸纳米微球的研发及CO_(2)驱封窜性能研究

针对长庆低渗透油藏CO_(2)驱出现的窜流难题,以丙烯酰胺(AM)、4-苯乙烯磺酸钠(SSS)和二甲基二烯丙基氯化铵(DMDAAC)为共聚单体,N,N’-亚甲基双丙烯酰胺(MBA)为交联剂,亚硫酸氢钠(SHS)和过硫酸铵(APS)为引发剂,通过反相微乳液聚合法研发了一种耐酸纳米微球(AR-NS)。采用红外光谱(FTIR)、扫描电镜(SEM)、热重(TG)及流变仪对产物的结构、形貌和性能进行了分析。结果表明,合成产物在乳液中为高分散度的纳米微球,其平均初始粒径为255 nm。在酸性地层水条件下,耐酸纳米微球的膨胀倍数为13.8倍而普通微球膨胀倍数仅为3.7倍;油藏温度85℃条件下、质量浓度为5 000 mg/L时耐酸纳米微球悬浮液黏度仅为0.56 mPa·s,具有优异的注入性;低渗裂缝岩心超临界CO_(2)驱封窜实验表明,耐酸纳米微球注入后裂缝性岩心的封堵率达95.41%,采收率提高了21.03%,耐酸纳米微球在低渗CO_(2)驱油藏中具有优异的封窜效果。

贫困生资助对大学生消费行为的影响:基于校园卡消费大数据和问卷调查数据的研究

基于某“双一流”大学本科生校园卡消费数据和学生发展情况调查数据,本文通过建立一般线性回归模型、双重差分模型和倾向性得分匹配模型,分析了贫困生资助对大学生消费行为的影响。研究发现:接受贫困生资助的学生在学校食堂就餐的次数更多、平均消费金额更低。利用倾向得分匹配和双重差分来消除选择性偏差的影响发现:贫困生资助仅对即期食堂消费水平有显著提升作用,而对学年平均食堂消费水平没有显著影响。这说明尽管受助学生与其他学生存在消费行为上的显著差异,但是贫困生资助对大学生消费水平仅产生短期效应而无中长期影响,日常餐饮消费并非贫困生资助的主要用途,若直接将补助发到餐卡未必能达到提高贫困生消费水平的目的。

Low Doses of Rifampicin Used in New Tuberculosis Patients Correlated to Increased Frequency of Rifampicin-Resistance and Poorer Treatment Outcomes

The prognosis of patients with previously treated tuberculosis (TB) was suggested to be dependent on whether the initial treatment was in compliance with the established guidelines. The aim of this retrospective multicenter study was to determine the proportion of new TB patients who received standard doses of rifampicin in multiple provinces of China, and the relationship between low doses of rifampicin and frequency of rifampicin-resistance as well as treatment outcomes. A total of 713 new TB patients were treated with either once-daily dose of bulk anti-TB drugs (group I) or every other day combination blister packs of anti-TB drugs containing rifampicin (group II) at more than 30 TB treatment centers/hospitals in China. Treatment history, therapeutic doses of rifampicin, and information about patients were extracted from their medical records and analyzed, and rifampicin-resistance of isolates collected from patients following the treatment as well as treatment outcomes were compared between two treatment groups. Among 522 patients in treatment group I, 154 (29.5%) received standard and 363 (69.5%) received low doses of rifampicin;238 (45.6%) isolates were rifampicin-resistant, and 243 (46.6%) were successfully treated. Among 191 patients in treatment group II, 175 (91.6%) received standard and 15 (7.9%) received low doses of rifampicin;72 (37.7%) isolates were rifampicin-resistant, and 105 (55%) were successfully treated. When patients who received low doses of rifampicin were compared to others within the same treatment group, increased rates for rifampicin-resistance and treatment failure were observed. Results from this study showed that most new TB patients in treatment group I (69.5%) received low doses of rifampicin, and their treatment outcomes were worse than those in treatment group II, indicating that low doses of rifampicin used for the initial treatment of new TB patients were correlated to increased frequency of rifampicin-resistance and poorer treatment outcomes.

Experimental and numerical simulation of lignite chemical looping gasification with phosphogypsum as oxygen carrier in a fluidized bed

Phosphogypsum(PG)is a solid waste produced in the wet process of producing phosphoric acid.Lignite is a kind of promising chemical raw material.However,the high sulfur of lignite limits the utilization of lignite as a resource.Based on fluidized bed experiments,the optimal reaction conditions for the production syngas by lignite chemical looping gasification(CLG)with PG as oxygen carrier were studied.The study found that the optimal reaction temperature should not exceed 1123 K;the mole ratio of water vapor to lignite should be about 0.2;the mole ratio of PG oxygen carrier to lignite should be about 0.6.Meanwhile,commercial software Comsol was used to establish a fuel reaction kinetics model.Through computational fluid dynamics(CFD)numerical simulation,the process of reaction in fluidized bed were well captured.The model was based on a two-fluid model and coupled mass transfer,heat transfer and chemical reactions.This study showed that the fluidized bed presents a flow structure in which gas and solid coexist.There was a high temperature zone in the middle and lower parts of the fluidized bed.It could be seen from the results of the flow field simulated that the fluidized bed was beneficial to the progress of the gasification reaction.

Molecular basis of the first cell fate determination in mouse embryogenesis

Through proliferation and differentiation, a single cell, the zygote, can give rise to a complex organism composed of many types of cells. Up to the eight-cell embryo stage, the blastomeres are morphologically identical and distributed symmetrically in the mammalian embryo. Functionally, in some species, they are all totipotent. However, due to the compaction of blastomeres and the asymmetrical cell division at the late phase of the eight-cell embryo, the blastomeres of the morula are no longer identical. During the transition from morula to blastocyst, blastomeres differentiate, resulting in the first cell fate decision in embryogenesis, namely, the segregation of the inner cell mass and the tropheetoderm. In this review, we will discuss the regulatory mechanisms essential for the cell fate choice during blastocyst development, including transcriptional regulation, epigenetic regulation, mieroRNAs, and signal transduction.

Analysis on Pollution Factors in Asparagus Production and Research on Safety Production Technology

Based on the analysis on the infection degree,infection law and influencing factors of the main diseases on asparagus and the analysis on the pollution factors in asparagus production such as blind pesticide use,atmospheric pollution and acid rain,the pollution of soil and fertilizer,this article proposes asparagus safety production technologies which include the selection of disease-resistant variety and suitable planting field,scientific and reasonable disease control,balanced fertilization,rational irrigation,making a good job of field management, etc.,to reduce pathogenic factors.

Mutual antagonism of mouse-adaptation mutations in HA and PA proteins on H9N2 virus replication

Avian H9N2 viruses have wide host range among the influenza A viruses.However,knowledge of H9N2 mammalian adaptation is limited.To explore the molecular basis of the adaptation to mammals,we performed serial lung passaging of the H9N2 strain A/chicken/Hunan/8.27 YYGK3W3-OC/2018(3W3)in mice and identified six mutations in the hemagglutinin(HA)and polymerase acidic(PA)proteins.Mutations L226Q,T511I,and A528V of HA were responsible for enhanced pathogenicity and viral replication in mice;notably,HA-L226Q was the key determinant.Mutations T97I,I545V,and S594G of PA contributed to enhanced polymerase activity in mammalian cells and increased viral replication levels in vitro and in vivo.PA-T97I increased viral polymerase activity by accelerating the viral polymerase complex assembly.Our findings revealed that the viral replication was affected by the presence of PA-97I and/or PA-545V in combination with a triple-point HA mutation.Furthermore,the double-and triple-point PA mutations demonstrated antagonistic effect on viral replication when combined with HA-226Q.Notably,any combination of PA mutations,along with double-point HA mutations,resulted in antagonistic effect on viral replication.We also observed antagonism in viral replication between PA-545V and PA-97I,as well as between HA-528V and PA-545V.Our findings demonstrated that several antagonistic mutations in HA and PA proteins affect viral replication,which may contribute to the H9N2 virus adaptation to mice and mammalian cells.These findings can potentially contribute to the monitoring of H9N2 field strains for assessing their potential risk in mammals.

Tenecteplase versus alteplase in treatment of acute ST-segment elevation myocardial infarction:A randomized non-inferiority trial

Background:A phase II trial on recombinant human tenecteplase tissue-type plasminogen activator(rhTNK-tPA)has previously shown its preliminary efficacy in ST elevation myocardial infarction(STEMI)patients.This study was designed as a pivotal postmarketing trial to compare its efficacy and safety with rrecombinant human tissue-type plasminogen activator alteplase(rt-PA)in Chinese patients with STEMI.Methods:In this multicenter,randomized,open-label,non-inferiority trial,patients with acute STEMI were randomly assigned(1:1)to receive an intravenous bolus of 16 mg rhTNK-tPA or an intravenous bolus of 8 mg rt-PA followed by an infusion of 42 mg in 90 min.The primary endpoint was recanalization defined by thrombolysis in myocardial infarction(TIMI)flow grade 2 or 3.The secondary endpoint was clinically justified recanalization.Other endpoints included 30-day major adverse cardiovascular and cerebrovascular events(MACCEs)and safety endpoints.Results:From July 2016 to September 2019,767 eligible patients were randomly assigned to receive rhTNK-tPA(n=384)or rt-PA(n=383).Among them,369 patients had coronary angiography data on TIMI flow,and 711 patients had data on clinically justified recanalization.Both used a–15%difference as the non-inferiority efficacy margin.In comparison to rt-PA,both the proportion of patients with TIMI grade 2 or 3 flow(78.3%[148/189]vs.81.7%[147/180];differences:–3.4%;95%confidence interval[CI]:–11.5%,4.8%)and clinically justified recanalization(85.4%[305/357]vs.85.9%[304/354];difference:–0.5%;95%CI:–5.6%,4.7%)in the rhTNK-tPA group were non-inferior.The occurrence of 30-day MACCEs(10.2%[39/384]vs.11.0%[42/383];hazard ratio:0.96;95%CI:0.61,1.50)did not differ significantly between groups.No safety outcomes significantly differed between groups.Conclusion:rhTNK-tPA was non-inferior to rt-PA in the effect of improving recanalization of the infarct-related artery,a validated surrogate of clinical outcomes,among Chinese patients with acute STEMI.Trial registration:www.ClinicalTrials.gov(No.NCT02835534).

Optimizing anaerobic digestion: Benefits of mild temperature transition from thermophilic to mesophilic conditions

Anaerobic digestion(AD)plays a significant role in renewable energy recovery.Upgrading AD from thermophilic(50e57C)to mesophilic(30e38C)conditions to enhance process stability and reduce energy input remains challenging due to the high sensitivity of thermophilic microbiomes to temperature fluctuations.Here we compare the effects of two decreasing-temperature modes from 55 to 35C on cell viability,microbial dynamics,and interspecies interactions.A sharp transition(ST)is a one-step transition by 20C d1,while a mild transition(MT)is a stepwise transition by 1C d1.We find a greater decrease in methane production with ST(88.8%)compared to MT(38.9%)during the transition period.ST mode overproduced reactive oxygen species by 1.6-fold,increased membrane permeability by 2.2-fold,and downregulated microbial energy metabolism by 25.1%,leading to increased apoptosis of anaerobes by 1.9-fold and release of intracellular substances by 2.9-fold,further constraining methanogenesis.The higher(1.6 vs.1.1 copies per gyrA)metabolic activity of acetate-dependent methanogenesis implied more efficient methane production in a steady mesophilic,MT-mediated system.Metagenomic binning and network analyses indicated that ST induced dysbiosis in keystone species and greatly enhanced microbial functional redundancy,causing loss of microbial syntrophic interactions and redundant metabolic pathways.In contrast,the greater microbial interconnections(average degrees 44.9 vs.22.1)in MT at a steady mesophilic state suggested that MT could better maintain necessary system functionality and stability through microbial syntrophy or specialized pathways.Adopting MT to transform thermophilic digesters into mesophilic digesters is feasible and could potentially enhance the further optimization and broader application of practical anaerobic engineering.

HPLC-MS/MS quantification of the HIV-1 protease inhibitor saquinavir in mice plasma and brain

In the present study, a rapid and sensitive liquid chromatography-tandem mass spectrometric method for the determination of saquinavir in mice plasma and brain was developed, validated, and applied to a preliminary screening study evaluating the effect of bioflavonoids on the brain distribution of saquinavir in mice. Saquinavir and the internal standard（ritonavir） were isolated from plasma and homogenized brain tissue matrices using a liquid-liquid extraction procedure, and the chromatographic separation was accomplished by using a reversed phase C18 column（150 mm×2.1 mm, 5.0 μm）. The analyte was detected by a triple-quadrupole tandem mass spectrometer via electrospray ionization, and multiple reaction monitoring was employed to select both saquinavir and ritonavir in the positive ion mode. A linear dynamic range of 0.1–10 ng/m L for plasma samples was established and the lower limit of quantification was 0.1 ng/m L. The intra- and inter-day precision were 7.5%–12.1%, and the accuracies ranged from 90.5% to 107.2% for plasma. A linear dynamic range of 0.1–10 ng/g for brain samples was established and the lower limit of quantification was 0.1 ng/g. The intra- and inter-day precision were 7.3%–11.9%, and the accuracies ranged from 90.8% to 107.4% for brain tissue samples. This method was successfully applied a preliminary screen of 19 bioflavonoids on the brain distribution of saquinavir in mice, and biochanin A shows the strongest effect.

Mechanisms of melatonin in anti-aging and its regulation effects in radiation-induced premature senescence

Melatonin is an effective antioxidant hormone produced mainly by the pineal gland.Premature senescence refers to senescence induced by declined cell proliferation and physiological functions when cells are stimulated by nontelomeric signals.The anti-aging effect of melatonin is exerted by upregulating the expression of silent information regulator 1/Sirtuin 1(SIRT1),which reduces oxidative stress damage,decreases p53 activation,and inhibits the NF-κB pathway.Radiation can induce premature senescence through direct or indirect oxidative stress damage.The mechanism by which melatonin regulates radiation-induced premature senescence includes the inhibition of the p53-mediated senescence pathway through elimination of reactive oxygen species or p53 deacetylation induced by upregulation of SIRT1 expression.Melatonin exhibits different regulatory effects for different cells and types of radiation.

典型有机固废厌氧消化微生物研究现状与发展方向

经过人工富集和驯化的兼性和严格厌氧微生物是厌氧消化工艺的核心。不同厌氧消化体系中存在的问题大多可以通过改变微生物群落的代谢活性来得到有效改善。得益于微生物组学检测技术的快速发展,对厌氧消化系统中微生物多样性的认识获得了极大的拓展,同时在微生物类群间、微生物与环境的互作关系研究方面也取得了一系列新的进展。然而,有机固废厌氧消化系统中,各种微生物以及微生物和物质的相互作用构成了更为复杂的代谢网络,所以目前对这些互作关系的解析尚不完善。本文重点关注了厌氧消化过程中的典型菌群互作关系,阐述了典型有机固废厌氧消化系统中存在的问题及微生物在其中发挥的作用,最后,立足于现有组学技术推动的微生物组研究进展,对未来有机固废厌氧消化系统微生物组的研究提出展望。

Twist1-induced miR-199a-3p promotes liver fibrosis by suppressing caveolin-2 and activating TGF-βpathway

The activation of hepatic stellate cells(HSCs)participates in liver fibrosis,and emerging evidences indicate that microRNAs(miRNAs)are abnormally expressed during HSC activation.However,the potential roles of miRNAs in liver fibrosis still remain elusive.Therefore,this study aimed to investigate the role of miR-199a-3p in liver fibrosis and its underlying mechanism.We found that miR-199a-3p expression was dramatically upregulated during HSC activation in vitro,and during liver fibrogenesis in CCl4-treated rats,and its liver expression was increased in the patients with cirrhosis.By the luciferase assay and RT-qPCR,we revealed that the expression of miR-199a-3p in HSCs was driven by the transcription factor Twist1 which could be further induced by TGF-βtreatment.Functional studies showed that inhibition of miR-199a-3p in both human LX2 cells and rat HSCs significantly decreased the expression of fibrotic markers,such as fibronectin and connective tissue growth factor(CTGF),whereas the forced expression of miR-199a-3p exhibited opposite effects,demonstrating the role of miR-199a-3p in promoting HSC activation.Mechanistically,miR-199a-3p plays an important role in TGF-βsignalling pathway activation through targeting CAV2 that negatively regulates the expression of transforming growth factor-beta receptor type I(TGFβRI).Importantly,administration of antagomiR-199a-3p in the CCl4-treated mice significantly ameliorated hepatic fibrosis.In conclusion,Twist1-induced miR-199a-3p mediates the activation of HSCs by suppressing CAV2 expression and subsequently increasing TGFβRI expression to promote TGF-βpathway.Our findings highlight the therapeutic potential of miR-199a-3p for hepatic fibrosis.

Low Pathogenic Avian Influenza A(H5N7) Virus Isolated from a Domestic Duck in Dongting Lake Wetland of China,2016

Dear Editor,The avian influenza virus (AIV) H5N7 was first isolated from wild birds in North America in 2001 (Spackman et al.2007), and information on only 25 strains of this virus has been deposited in the Global Initiative on Sharing All Influenza Data (GISAID-http://platform.gisaid.org/epi3/frontend#493de3) database until October 30, 2018. Twenty viruses were identified in the United States from 2001 to2017.